/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2002-2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.hibernate.exception;
import org.hibernate.util.ArrayHelper;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.StringTokenizer;
/**
* <p>Provides utilities for manipulating and examining
* <code>Throwable</code> objects.</p>
*
* @author <a href="mailto:[email protected]">Daniel Rall</a>
* @author Dmitri Plotnikov
* @author Stephen Colebourne
* @author <a href="mailto:[email protected]">Gary Gregory</a>
* @author Pete Gieser
* @version $Id: ExceptionUtils.java 4782 2004-11-21 00:11:27Z pgmjsd $
* @since 1.0
*/
public final class ExceptionUtils {
private static final String LINE_SEPARATOR = System.getProperty( "line.separator" );
/**
* <p>Used when printing stack frames to denote the start of a
* wrapped exception.</p>
* <p/>
* <p>Package private for accessibility by test suite.</p>
*/
static final String WRAPPED_MARKER = " [wrapped] ";
/**
* <p>The names of methods commonly used to access a wrapped exception.</p>
*/
private static final String[] CAUSE_METHOD_NAMES = {
"getCause",
"getNextException",
"getTargetException",
"getException",
"getSourceException",
"getRootCause",
"getCausedByException",
"getNested"
};
/**
* <p>The Method object for JDK1.4 getCause.</p>
*/
private static final Method THROWABLE_CAUSE_METHOD;
static {
Method getCauseMethod;
try {
getCauseMethod = Throwable.class.getMethod( "getCause", null );
}
catch ( Exception e ) {
getCauseMethod = null;
}
THROWABLE_CAUSE_METHOD = getCauseMethod;
}
private ExceptionUtils() {
}
//-----------------------------------------------------------------------
/**
* <p>Adds to the list of method names used in the search for <code>Throwable</code>
* objects.</p>
*
* @param methodName the methodName to add to the list, <code>null</code>
* and empty strings are ignored
* @since 2.0
*/
/*public static void addCauseMethodName(String methodName) {
if ( StringHelper.isNotEmpty(methodName) ) {
List list = new ArrayList( Arrays.asList(CAUSE_METHOD_NAMES );
list.add(methodName);
CAUSE_METHOD_NAMES = (String[]) list.toArray(new String[list.size()]);
}
}*/
/**
* <p>Introspects the <code>Throwable</code> to obtain the cause.</p>
* <p/>
* <p>The method searches for methods with specific names that return a
* <code>Throwable</code> object. This will pick up most wrapping exceptions,
* including those from JDK 1.4, and
* {@link org.apache.commons.lang.exception.NestableException NestableException}.
* The method names can be added to using {@link #addCauseMethodName(String)}.</p>
* <p/>
* <p>The default list searched for are:</p>
* <ul>
* <li><code>getCause()</code></li>
* <li><code>getNextException()</code></li>
* <li><code>getTargetException()</code></li>
* <li><code>getException()</code></li>
* <li><code>getSourceException()</code></li>
* <li><code>getRootCause()</code></li>
* <li><code>getCausedByException()</code></li>
* <li><code>getNested()</code></li>
* </ul>
* <p/>
* <p>In the absence of any such method, the object is inspected for a
* <code>detail</code> field assignable to a <code>Throwable</code>.</p>
* <p/>
* <p>If none of the above is found, returns <code>null</code>.</p>
*
* @param throwable the throwable to introspect for a cause, may be null
* @return the cause of the <code>Throwable</code>,
* <code>null</code> if none found or null throwable input
*/
public static Throwable getCause(Throwable throwable) {
return getCause( throwable, CAUSE_METHOD_NAMES );
}
/**
* <p>Introspects the <code>Throwable</code> to obtain the cause.</p>
* <p/>
* <ol>
* <li>Try known exception types.</li>
* <li>Try the supplied array of method names.</li>
* <li>Try the field 'detail'.</li>
* </ol>
* <p/>
* <p>A <code>null</code> set of method names means use the default set.
* A <code>null</code> in the set of method names will be ignored.</p>
*
* @param throwable the throwable to introspect for a cause, may be null
* @param methodNames the method names, null treated as default set
* @return the cause of the <code>Throwable</code>,
* <code>null</code> if none found or null throwable input
*/
public static Throwable getCause(Throwable throwable, String[] methodNames) {
if ( throwable == null ) {
return null;
}
Throwable cause = getCauseUsingWellKnownTypes( throwable );
if ( cause == null ) {
if ( methodNames == null ) {
methodNames = CAUSE_METHOD_NAMES;
}
for ( int i = 0; i < methodNames.length; i++ ) {
String methodName = methodNames[i];
if ( methodName != null ) {
cause = getCauseUsingMethodName( throwable, methodName );
if ( cause != null ) {
break;
}
}
}
if ( cause == null ) {
cause = getCauseUsingFieldName( throwable, "detail" );
}
}
return cause;
}
/**
* <p>Introspects the <code>Throwable</code> to obtain the root cause.</p>
* <p/>
* <p>This method walks through the exception chain to the last element,
* "root" of the tree, using {@link #getCause(Throwable)}, and
* returns that exception.</p>
*
* @param throwable the throwable to get the root cause for, may be null
* @return the root cause of the <code>Throwable</code>,
* <code>null</code> if none found or null throwable input
*/
public static Throwable getRootCause(Throwable throwable) {
Throwable cause = getCause( throwable );
if ( cause != null ) {
throwable = cause;
while ( ( throwable = getCause( throwable ) ) != null ) {
cause = throwable;
}
}
return cause;
}
/**
* <p>Finds a <code>Throwable</code> for known types.</p>
* <p/>
* <p>Uses <code>instanceof</code> checks to examine the exception,
* looking for well known types which could contain chained or
* wrapped exceptions.</p>
*
* @param throwable the exception to examine
* @return the wrapped exception, or <code>null</code> if not found
*/
private static Throwable getCauseUsingWellKnownTypes(Throwable throwable) {
if ( throwable instanceof Nestable ) {
return ( ( Nestable ) throwable ).getCause();
}
else if ( throwable instanceof SQLException ) {
return ( ( SQLException ) throwable ).getNextException();
}
else if ( throwable instanceof InvocationTargetException ) {
return ( ( InvocationTargetException ) throwable ).getTargetException();
}
else {
return null;
}
}
/**
* <p>Finds a <code>Throwable</code> by method name.</p>
*
* @param throwable the exception to examine
* @param methodName the name of the method to find and invoke
* @return the wrapped exception, or <code>null</code> if not found
*/
private static Throwable getCauseUsingMethodName(Throwable throwable, String methodName) {
Method method = null;
try {
method = throwable.getClass().getMethod( methodName, null );
}
catch ( NoSuchMethodException ignored ) {
}
catch ( SecurityException ignored ) {
}
if ( method != null && Throwable.class.isAssignableFrom( method.getReturnType() ) ) {
try {
return ( Throwable ) method.invoke( throwable, ArrayHelper.EMPTY_OBJECT_ARRAY );
}
catch ( IllegalAccessException ignored ) {
}
catch ( IllegalArgumentException ignored ) {
}
catch ( InvocationTargetException ignored ) {
}
}
return null;
}
/**
* <p>Finds a <code>Throwable</code> by field name.</p>
*
* @param throwable the exception to examine
* @param fieldName the name of the attribute to examine
* @return the wrapped exception, or <code>null</code> if not found
*/
private static Throwable getCauseUsingFieldName(Throwable throwable, String fieldName) {
Field field = null;
try {
field = throwable.getClass().getField( fieldName );
}
catch ( NoSuchFieldException ignored ) {
}
catch ( SecurityException ignored ) {
}
if ( field != null && Throwable.class.isAssignableFrom( field.getType() ) ) {
try {
return ( Throwable ) field.get( throwable );
}
catch ( IllegalAccessException ignored ) {
}
catch ( IllegalArgumentException ignored ) {
}
}
return null;
}
//-----------------------------------------------------------------------
/**
* <p>Checks if the Throwable class has a <code>getCause</code> method.</p>
* <p/>
* <p>This is true for JDK 1.4 and above.</p>
*
* @return true if Throwable is nestable
* @since 2.0
*/
public static boolean isThrowableNested() {
return ( THROWABLE_CAUSE_METHOD != null );
}
/**
* <p>Checks whether this <code>Throwable</code> class can store a cause.</p>
* <p/>
* <p>This method does <b>not</b> check whether it actually does store a cause.<p>
*
* @param throwable the <code>Throwable</code> to examine, may be null
* @return boolean <code>true</code> if nested otherwise <code>false</code>
* @since 2.0
*/
public static boolean isNestedThrowable(Throwable throwable) {
if ( throwable == null ) {
return false;
}
if ( throwable instanceof Nestable ) {
return true;
}
else if ( throwable instanceof SQLException ) {
return true;
}
else if ( throwable instanceof InvocationTargetException ) {
return true;
}
else if ( isThrowableNested() ) {
return true;
}
Class cls = throwable.getClass();
for ( int i = 0, isize = CAUSE_METHOD_NAMES.length; i < isize; i++ ) {
try {
Method method = cls.getMethod( CAUSE_METHOD_NAMES[i], null );
if ( method != null && Throwable.class.isAssignableFrom( method.getReturnType() ) ) {
return true;
}
}
catch ( NoSuchMethodException ignored ) {
}
catch ( SecurityException ignored ) {
}
}
try {
Field field = cls.getField( "detail" );
if ( field != null ) {
return true;
}
}
catch ( NoSuchFieldException ignored ) {
}
catch ( SecurityException ignored ) {
}
return false;
}
//-----------------------------------------------------------------------
/**
* <p>Counts the number of <code>Throwable</code> objects in the
* exception chain.</p>
* <p/>
* <p>A throwable without cause will return <code>1</code>.
* A throwable with one cause will return <code>2</code> and so on.
* A <code>null</code> throwable will return <code>0</code>.</p>
*
* @param throwable the throwable to inspect, may be null
* @return the count of throwables, zero if null input
*/
public static int getThrowableCount(Throwable throwable) {
int count = 0;
while ( throwable != null ) {
count++;
throwable = ExceptionUtils.getCause( throwable );
}
return count;
}
/**
* <p>Returns the list of <code>Throwable</code> objects in the
* exception chain.</p>
* <p/>
* <p>A throwable without cause will return an array containing
* one element - the input throwable.
* A throwable with one cause will return an array containing
* two elements. - the input throwable and the cause throwable.
* A <code>null</code> throwable will return an array size zero.</p>
*
* @param throwable the throwable to inspect, may be null
* @return the array of throwables, never null
*/
public static Throwable[] getThrowables(Throwable throwable) {
List list = new ArrayList();
while ( throwable != null ) {
list.add( throwable );
throwable = ExceptionUtils.getCause( throwable );
}
return ( Throwable[] ) list.toArray( new Throwable[list.size()] );
}
//-----------------------------------------------------------------------
/**
* <p>Returns the (zero based) index of the first <code>Throwable</code>
* that matches the specified type in the exception chain.</p>
* <p/>
* <p>A <code>null</code> throwable returns <code>-1</code>.
* A <code>null</code> type returns <code>-1</code>.
* No match in the chain returns <code>-1</code>.</p>
*
* @param throwable the throwable to inspect, may be null
* @param type the type to search for
* @return the index into the throwable chain, -1 if no match or null input
*/
public static int indexOfThrowable(Throwable throwable, Class type) {
return indexOfThrowable( throwable, type, 0 );
}
/**
* <p>Returns the (zero based) index of the first <code>Throwable</code>
* that matches the specified type in the exception chain from
* a specified index.</p>
* <p/>
* <p>A <code>null</code> throwable returns <code>-1</code>.
* A <code>null</code> type returns <code>-1</code>.
* No match in the chain returns <code>-1</code>.
* A negative start index is treated as zero.
* A start index greater than the number of throwables returns <code>-1</code>.</p>
*
* @param throwable the throwable to inspect, may be null
* @param type the type to search for
* @param fromIndex the (zero based) index of the starting position,
* negative treated as zero, larger than chain size returns -1
* @return the index into the throwable chain, -1 if no match or null input
*/
public static int indexOfThrowable(Throwable throwable, Class type, int fromIndex) {
if ( throwable == null ) {
return -1;
}
if ( fromIndex < 0 ) {
fromIndex = 0;
}
Throwable[] throwables = ExceptionUtils.getThrowables( throwable );
if ( fromIndex >= throwables.length ) {
return -1;
}
for ( int i = fromIndex; i < throwables.length; i++ ) {
if ( throwables[i].getClass().equals( type ) ) {
return i;
}
}
return -1;
}
//-----------------------------------------------------------------------
/**
* <p>Prints a compact stack trace for the root cause of a throwable
* to <code>System.err</code>.</p>
* <p/>
* <p>The compact stack trace starts with the root cause and prints
* stack frames up to the place where it was caught and wrapped.
* Then it prints the wrapped exception and continues with stack frames
* until the wrapper exception is caught and wrapped again, etc.</p>
* <p/>
* <p>The method is equivalent to <code>printStackTrace</code> for throwables
* that don't have nested causes.</p>
*
* @param throwable the throwable to output
* @since 2.0
*/
public static void printRootCauseStackTrace(Throwable throwable) {
printRootCauseStackTrace( throwable, System.err );
}
/**
* <p>Prints a compact stack trace for the root cause of a throwable.</p>
* <p/>
* <p>The compact stack trace starts with the root cause and prints
* stack frames up to the place where it was caught and wrapped.
* Then it prints the wrapped exception and continues with stack frames
* until the wrapper exception is caught and wrapped again, etc.</p>
* <p/>
* <p>The method is equivalent to <code>printStackTrace</code> for throwables
* that don't have nested causes.</p>
*
* @param throwable the throwable to output, may be null
* @param stream the stream to output to, may not be null
* @throws IllegalArgumentException if the stream is <code>null</code>
* @since 2.0
*/
public static void printRootCauseStackTrace(Throwable throwable, PrintStream stream) {
if ( throwable == null ) {
return;
}
if ( stream == null ) {
throw new IllegalArgumentException( "The PrintStream must not be null" );
}
String trace[] = getRootCauseStackTrace( throwable );
for ( int i = 0; i < trace.length; i++ ) {
stream.println( trace[i] );
}
stream.flush();
}
/**
* <p>Prints a compact stack trace for the root cause of a throwable.</p>
* <p/>
* <p>The compact stack trace starts with the root cause and prints
* stack frames up to the place where it was caught and wrapped.
* Then it prints the wrapped exception and continues with stack frames
* until the wrapper exception is caught and wrapped again, etc.</p>
* <p/>
* <p>The method is equivalent to <code>printStackTrace</code> for throwables
* that don't have nested causes.</p>
*
* @param throwable the throwable to output, may be null
* @param writer the writer to output to, may not be null
* @throws IllegalArgumentException if the writer is <code>null</code>
* @since 2.0
*/
public static void printRootCauseStackTrace(Throwable throwable, PrintWriter writer) {
if ( throwable == null ) {
return;
}
if ( writer == null ) {
throw new IllegalArgumentException( "The PrintWriter must not be null" );
}
String trace[] = getRootCauseStackTrace( throwable );
for ( int i = 0; i < trace.length; i++ ) {
writer.println( trace[i] );
}
writer.flush();
}
//-----------------------------------------------------------------------
/**
* <p>Creates a compact stack trace for the root cause of the supplied
* <code>Throwable</code>.</p>
*
* @param throwable the throwable to examine, may be null
* @return an array of stack trace frames, never null
* @since 2.0
*/
public static String[] getRootCauseStackTrace(Throwable throwable) {
if ( throwable == null ) {
return ArrayHelper.EMPTY_STRING_ARRAY;
}
Throwable throwables[] = getThrowables( throwable );
int count = throwables.length;
ArrayList frames = new ArrayList();
List nextTrace = getStackFrameList( throwables[count - 1] );
for ( int i = count; --i >= 0; ) {
List trace = nextTrace;
if ( i != 0 ) {
nextTrace = getStackFrameList( throwables[i - 1] );
removeCommonFrames( trace, nextTrace );
}
if ( i == count - 1 ) {
frames.add( throwables[i].toString() );
}
else {
frames.add( WRAPPED_MARKER + throwables[i].toString() );
}
for ( int j = 0; j < trace.size(); j++ ) {
frames.add( trace.get( j ) );
}
}
return ( String[] ) frames.toArray( new String[0] );
}
/**
* <p>Removes common frames from the cause trace given the two stack traces.</p>
*
* @param causeFrames stack trace of a cause throwable
* @param wrapperFrames stack trace of a wrapper throwable
* @throws IllegalArgumentException if either argument is null
* @since 2.0
*/
public static void removeCommonFrames(List causeFrames, List wrapperFrames) {
if ( causeFrames == null || wrapperFrames == null ) {
throw new IllegalArgumentException( "The List must not be null" );
}
int causeFrameIndex = causeFrames.size() - 1;
int wrapperFrameIndex = wrapperFrames.size() - 1;
while ( causeFrameIndex >= 0 && wrapperFrameIndex >= 0 ) {
// Remove the frame from the cause trace if it is the same
// as in the wrapper trace
String causeFrame = ( String ) causeFrames.get( causeFrameIndex );
String wrapperFrame = ( String ) wrapperFrames.get( wrapperFrameIndex );
if ( causeFrame.equals( wrapperFrame ) ) {
causeFrames.remove( causeFrameIndex );
}
causeFrameIndex--;
wrapperFrameIndex--;
}
}
//-----------------------------------------------------------------------
/**
* <p>Gets the stack trace from a Throwable as a String.</p>
*
* @param throwable the <code>Throwable</code> to be examined
* @return the stack trace as generated by the exception's
* <code>printStackTrace(PrintWriter)</code> method
*/
public static String getStackTrace(Throwable throwable) {
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter( sw, true );
throwable.printStackTrace( pw );
return sw.getBuffer().toString();
}
/**
* <p>A way to get the entire nested stack-trace of an throwable.</p>
*
* @param throwable the <code>Throwable</code> to be examined
* @return the nested stack trace, with the root cause first
* @since 2.0
*/
public static String getFullStackTrace(Throwable throwable) {
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter( sw, true );
Throwable[] ts = getThrowables( throwable );
for ( int i = 0; i < ts.length; i++ ) {
ts[i].printStackTrace( pw );
if ( isNestedThrowable( ts[i] ) ) {
break;
}
}
return sw.getBuffer().toString();
}
//-----------------------------------------------------------------------
/**
* <p>Captures the stack trace associated with the specified
* <code>Throwable</code> object, decomposing it into a list of
* stack frames.</p>
*
* @param throwable the <code>Throwable</code> to exaamine, may be null
* @return an array of strings describing each stack frame, never null
*/
public static String[] getStackFrames(Throwable throwable) {
if ( throwable == null ) {
return ArrayHelper.EMPTY_STRING_ARRAY;
}
return getStackFrames( getStackTrace( throwable ) );
}
/**
* <p>Functionality shared between the
* <code>getStackFrames(Throwable)</code> methods of this and the
* {@link org.apache.commons.lang.exception.NestableDelegate}
* classes.</p>
*/
static String[] getStackFrames(String stackTrace) {
String linebreak = LINE_SEPARATOR;
StringTokenizer frames = new StringTokenizer( stackTrace, linebreak );
List list = new LinkedList();
while ( frames.hasMoreTokens() ) {
list.add( frames.nextToken() );
}
return ( String[] ) list.toArray( new String[list.size()] );
}
/**
* <p>Produces a <code>List</code> of stack frames - the message
* is not included.</p>
* <p/>
* <p>This works in most cases - it will only fail if the exception
* message contains a line that starts with:
* <code>" at".</code></p>
*
* @param t is any throwable
* @return List of stack frames
*/
static List getStackFrameList(Throwable t) {
String stackTrace = getStackTrace( t );
String linebreak = LINE_SEPARATOR;
StringTokenizer frames = new StringTokenizer( stackTrace, linebreak );
List list = new LinkedList();
boolean traceStarted = false;
while ( frames.hasMoreTokens() ) {
String token = frames.nextToken();
// Determine if the line starts with <whitespace>at
int at = token.indexOf( "at" );
if ( at != -1 && token.substring( 0, at ).trim().length() == 0 ) {
traceStarted = true;
list.add( token );
}
else if ( traceStarted ) {
break;
}
}
return list;
}
}
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